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Cardiovascular fitness It is very important to remember that cardiovascular fitness is not just for top sportspeople It is the most important aspect of fitness for all of us because it involves the circulatory and the respiratory systems The heart or cardiac muscle is different to any other muscle in that it never tires. It must continually pump blood — without it, we would die. If the blood vessels become blocked or hardened, angina or heart attack occurs Improved cardiovascular fitness increases the number of blood vessels in and around the heart, so reducing the risk of a heart attack

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Body changes during exercise Cell respiration in the muscles and the level of carbon dioxide in the blood increase The brain detects this and sends a signal to the lungs to breathe faster and deeper Gas exchange in the lungs speeds up More carbon dioxide passes out of the blood and more oxygen passes into it The brain also sends a signal to the heart to beat faster, making the heart rate go up The muscles squeeze on veins, sending more blood back to the heart — this helps the stroke volume (SV) to increase

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Body changes during exercise Cardiac output rises — more blood gets pumped to the muscles each minute This means more oxygen reaches the muscles each minute and more carbon dioxide is carried away Arterioles widen so that your blood pressure won’t get too high Blood gets moved to where it is needed from where it is less needed, eg from your gut to your legs To make this happen, blood vessels widen and constrict at different points (vasodilation and vasoconstriction)

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Body changes during exercise Exercise generates heat, making the body hotter Blood is directed close to the skin to cool down This makes the skin redden The body is also cooled by sweating, through evaporation Blood flow to skeletal muscles increases Movement at joints may increase markedly

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Effects on circulatory system Increase in blood volume — more blood in the body means more haemoglobin and, therefore, more oxygen when it is needed, eg during exercise. So there is greater endurance Heart muscle gets bigger and stronger — with each beat, or stroke, the heart will pump out more blood. The heart rate of a fit person will be lower than an unfit person and the heart will pump out greater quantities of blood (increased stroke volume). Therefore, whatever the level of exercise, and whatever the body’s oxygen requirement, the fit person will need fewer beats of the heart to meet the requirement than an unfit person

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Effects on circulatory system Lung capacity increases — more oxygen can be breathed in when needed and more carbon dioxide can be breathed out The heart’s workload is reduced — if the heart does not need to beat as often, it will probably last longer which could mean a longer life Less chance of heart disease — harmful cholesterol is less likely to build up in the coronary arteries of a fit person than in an unfit person. Cholesterol in the coronary arteries can cause fatal heart attacks

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Effects on circulatory system Increase in capillary network so more efficient gas exchange — regular exercise results in an increase in the number of capillaries between each artery and vein. This means more efficient exchange through the capillary walls of oxygen for carbon dioxide and muscle fuel for waste products, ie tissue respiration becomes more efficient Blood supply to the heart increases — this is due to the increased number of capillaries around the heart muscle. This makes the heart stronger and more efficient

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Effects of regular training Promotes bone strength and thickness — a physically fit person will have stronger and slightly thicker bones than an unfit person. This means the fit person will be more resistant to breaks and will be able to take much harder blows Keeps weight down — but only with a sensible diet

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Effects of regular training Performance in sport will improve — this is due to an improved aerobic base (a person’s basic level of aerobic fitness). If a person has basic fitness, they will perform better in sport. For example, a footballer may have superb ball skills, but if he is unfit he will not be able to use them in a competitive match Less fatigue means less injury — many injuries in sport occur towards the end of the game when a player is fatigued. Therefore, the fitter the player, the less likely they will be to suffer injuries

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Weight loss Exercising for 30 minutes a day can help weight loss Reducing your weight by just ten lbs (4 kg) may be enough to lower blood pressure Losing weight can help to enhance the effects of high blood pressure medication It may also reduce the risk of other conditions, such as diabetes, heart attack, breast cancer, obesity, high blood cholesterol and stroke

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General benefits of exercise Improved health Stronger muscles Better flexibility Improved posture Improved heart and lung system Better appetite Feeling more relaxed Better social life Improved quality of life Reduced risk of disease and ill-health